The Great Depression: What Caused It and How it Ended

10. Japan Attacks the U.S.

Understanding how entering World War II helped the U.S. dig itself out of the Great Depression involves learning principles of Keynesian economics. Economist John Maynard Keynes claimed that depressed economies recover when demand for services and goods increase. Since you need people to make products or provide services, employment rates naturally rise, and workers once again have money to spend. With the onset of U.S. involvement in World War II, between 1941 and 1943 government purchases from manufacturers quadrupled. This added substantial demand to the American economy.

traveler1116 / Getty Images